Rotary compressor

ABSTRACT

A capacity control system for a rotary gas compressor of the sliding vane type having a rotor placed eccentrically within a working chamber provided by the cylinder of a stator housing, the rotor carrying blades or vanes freely slidable in slots in the rotor to engage the cylinder. A control plate is positioned between the rotor and one of the housing cover plates and has an arcuate aperture providing a flow path for refrigerant gas. The control plate is rotatably adjustable to locate the aperture in relation to slots in the rotor periphery, between the blades, to vary the effective size of the compression chamber.

United States Patent [1 1 Newton Mar. 26, 1974 ROTARY COMPRESSOR PrimaryExaminerC. J. Husar Assistant Examiner-Leonard Smith [75] Inventor AIM.B. Newton York 133' Attorney, Agent, or Firm-Donald W. Banner [73]Assignee: Borg-Warner Corporation, Chicago,

57 ABSTRACT [22] Filed: June 12, 1972 1 A capacity control system for arotary gas compressor pp No: 261,830 of the sliding vane type having arotor placed eccentrically within a working chamber provided by thecylin- 52 us. (:1 418/77, 418/78, 418/79, def Of a Stator using, therotor carrying blades 0r 418/270 vanes freely slidable in slots in therotor to engage the 51 Int. Cl. F04c 15/04 cylinden A Control Plate isPSltined between [58 Field of Search 1. 418/16, 30, 183, 77, 78, rotorand one of the housing Plates and has 418/79 270 arcuate apertureproviding a flow path for refrigerant gas. The control plate isrotatably adjustable to locate [56] References Cited the aperture inrelation to slots in the rotor periphery, UNITED STATES PATENTS betweenthe blades, to vary the effective size of the compression chamber.3,l20,8l4 2/1964 Mueller 417/310 6 Claims, 2 Drawing Figures 1 ROTARYCOMPRESSOR SUMMARY or THE INVENTION This invention relates to gascompressors and more particularly to capacity control systems for rotarygas compressors.

.One type of conventional rotary gas compressor comprises a bladed rotoreccentrically mounted in a cylindrical statorhousing including inlet orsuction and outlet or discharge ports communicating with acrescent-shaped working chamber defined between the rotor and housing.In operation, displacement of the rotary compressor is essentiallyconstant per revolution.

The rotary gas compressor of the present invention is characterized bythe provision of a capacity control system including a compressioncontrol member in the form of a plate rotatably positioned between thebladed rotor and its stator housing and carried by the housing, theplate having control passages cooperating with control slots in therotor periphery between the blades to vent the gas compression chamberto the suction side of the compressor in response to rotation of theplate to thereby control the effective size of the compression chamberand the amount of capacity of the compressor so as to establish adesired setting conducive to its most efficient operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view-of arotary gas compressor having an improved capacity control system; and

FIG. 2 is a cross-sectional view taken along the plane of line 2-2 ofFIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1 and 2, thegas compressor embodies the improved control system of the presentinvention and comprises a rotor assembly 11 rotatable within a statorassembly 12 and which serves as a housing for the rotor assembly. Moreparticularly, the stator assembly 12 comprises a housing including anannular member 13 and cover plates 14 and 15 providing end walls closingthe open ends of the annular member 13 and held in engagement with thesame by a plurality of bolts 16. The plates 14 and 15 are bored as at 17and 18 to provide bearings for rotatably mounting the rotor assembly 11.

The rotor assembly 11 comprises a cylindrical rotor 19 having aplurality of equidistantly-spaced slots 20 adapted to receive vanes orblades 21 slidable reciprocally therein. Rotor 19 is keyed at 22 to adrive shaft 23 journalled in the bearings 17 and 18 in plates 14 and 15of the stator assembly and rotated by a pulley 24 driven by a motor (notshown) or other suitable drive means. In the case of an automotiveapplication, the compressor is usually driven from the engine through anaccessory drive system.

As shown in FIG. 2, the hollow substantially cylindrical inner surface25 of the stator housing is provided with contact area 26. Since therotor is rotatably mounted on an axis 27 offset from the center-line ofthe cylinder 25, the rotor is substantially in sliding contact with thecylinder at 26, leaving a generally crescentshaped working chamber 28extending over a substantial portion of the inner periphery of thestator housing 13. The direction of rotation of the rotor is indicatedby the arrow in FIG. 2.v

As shown in FIG. 2, the annularmember 13 of the stator housing isprovided with a suction or inlet port 29 connected to the chamber 28.Also, a discharge or outlet port 30 is provided in the annular member13, the port 30 communicating with the working chamber 28.

The improved control system comprises the slots 32, which are formed inthe periphery of the rotor and are of small volume and disposed neartheleading edge of each vane. If desired, the slots may be locatedelsewhere, even adjacent the trailing edges of the vanes. The systemincludes an annular member or plate 33 positioned within a cylindricalrecess or cavity 34 in the housing end plate 15 and between the rotor 19and plate 15, the drive shaft 23 extending through the central openingin the plate 33. The cylindrical cavity 34.

in the housing has its center located eccentrically to the center of thehousing surface 25 and concentric with the axis of the rotor so that itcompletely covers the contiguous side of the rotor. The control plate 33is rotatable in the housing recess 34 by a pinion or gear 35 having itsteeth meshedwith the ring gear teeth 36 on the side of the plate 33. Thepinion 35 is formed or fitted on the inner end of an operating shaft 37mounted in a suitable sleeve bearing 38 in the end plate 15 andextending upwardly and exteriorly of the plate 15 so as to be manuallyrotatable by the knurled knob 39 fixed to the shaft 37 to rotate thecontrol plate 33.

As shown in FIG. 2, the annular control plate 33 is provided with anarcuately-shaped aperture 40. The slots 32 in the rotor peripherycommunicate with the working chamber 28 and are located to intercept thearcuate aperture 40 in the plate 33 upon rotation of the a rotor. Theaperture is of such length as to span the distance between any twoadjacent slots.

In the operation of the control system, the control plate 33 isoperative to vary the effective length of the suction portion of theworking chamber 28 and its corresponding volume. More particularly, whenthe plate is moved to the position shown in FIG. 2, the aperture 40 islocated in its extreme clockwise position so that the suction is notclosed until a point close to the discharge port 30. When the plate 33is moved to its extreme couner-clockwise position, the suction closes ata point much closer to the inlet port 29 and the volume of gas admittedis correspondingly larger and the compressor capacity is increased.

It will be apparent that there is provided an improved and satisfactorysystem for controlling the existence and the amount of capacityreduction of rotary compressors with a minimum of loss in efficiency.

What is claimed is:

1. A rotary compressor comprising a housing having a closed workingchamber provided with a substantially cylindrical surface, said housinghaving an inlet port and an outlet port communicating with said chamber;a rotor mounted in said chamber and rotatable about an axis eccentric tothe axis of said cylindrical surface, said rotor having contact withsaid cylindrical surface at one point on its periphery, and a pluralityof vanes slidably supported in said rotor and engaging said cylindricalsurface, said rotor having slots in the periphery thereof between saidvanes and each slot communicating with said chamber; and a controlmember mounted in said housing and provided with an aperture capable ofspanning two adjacent rotor slots and operative to connect slotsconsecutively positioned in communication therewith by rotation of saidrotor, said control member being positioned in said housing to vent thecompression side of the chamber, through said aperture and the slotsconnectible thereto, to the suction side of the chamber to control thecapacity of the compressor.

2. A rotary compressor as defined in claim 1 in which said controlmember is rotatable relative to said housing for adjustment to differentpositions effective to vary the capacity of the compressor.

3. A rotary compressor as defined in claim 1 in which said controlmember comprises an annular plate engaging one side of said rotor andwhich side is provided with said slots connectible to said aperture ofsaid plate.

4. A rotary compressor as defined in claim 4 in which said plate isrotatable about the axis of rotation of said rotor for adjustment todifferent positions effective to vary the capacity of the compressor.

5. A rotary compressor as defined in claim 1 in which said housingcomprises an annular member having said inlet port and cylindricalsurface, and spaced walls closing the open ends of said annular memberto provide said chamber with one of said walls having a recess, and saidcontrol member comprising an annular plate concentric to the axis ofsaid rotor and mounted in said recess to engage the side of said rotor.

6. A rotary compressor as defined in claim 5 in which said control plateis rotatable relative to said rotor and said housing for adjustment todifferent positions effective to vary the capacity of the compressor.

1. A rotary compressor comprising a housing having a closed workingchamber provided with a substantially cylindrical surface, said housinghaving an inlet port and an outlet port communicating with said chamber;a rotor mounted in said chamber and rotatable about an axis eccentric tothe axis of said cylindrical surface, said rotor having contact withsaid cylindrical surface at one point on its periphery, and a pluralityof vanes slidably supported in said rotor and engaging said cylindricalsurface, said rotor having slots in the periphery thereof between saidvanes and each slot communicating with said chamber; and a controlmember mounted in said housing and provided with an aperture capable ofspanning two adjacent rotor slots and operative to connect slotsconsecutively positioned in communication therewith by rotation of saidrotor, said control member being positioned in said housing to vent thecompression side of the chamber, through said aperture and the slotsconnectible thereto, to the suction side of the chamber to control thecapacity of the compressor.
 2. A rotary compressor as defined in claim 1in which said control membEr is rotatable relative to said housing foradjustment to different positions effective to vary the capacity of thecompressor.
 3. A rotary compressor as defined in claim 1 in which saidcontrol member comprises an annular plate engaging one side of saidrotor and which side is provided with said slots connectible to saidaperture of said plate.
 4. A rotary compressor as defined in claim 4 inwhich said plate is rotatable about the axis of rotation of said rotorfor adjustment to different positions effective to vary the capacity ofthe compressor.
 5. A rotary compressor as defined in claim 1 in whichsaid housing comprises an annular member having said inlet port andcylindrical surface, and spaced walls closing the open ends of saidannular member to provide said chamber with one of said walls having arecess, and said control member comprising an annular plate concentricto the axis of said rotor and mounted in said recess to engage the sideof said rotor.
 6. A rotary compressor as defined in claim 5 in whichsaid control plate is rotatable relative to said rotor and said housingfor adjustment to different positions effective to vary the capacity ofthe compressor.